P04F4

Catalyst Heater Circuit Low Bank 1

Severity

⚠️ Medium

Can you drive?

Limited driving only, diagnose soon

Approx. repair cost

$56–167 (est.)

Symptoms

Check Engine Light Is On
Increased fuel consumption
Reduced catalytic converter efficiency

Causes

Open or short circuit in wiring harness
Heating relay malfunction
Blown fuse
Defective heating element of the neutralizer
Problems with the engine control unit

How to Fix

Check the condition of the heating circuit fuse
Inspect the wiring harness for damage
Check the functionality of the heating relay
Test the resistance of the heating element
Replace damaged components if necessary
Reset the error and check the system operation

Related codes

P0420 P0430 P0135